<template>
  <div
    class="demo-block"
    :class="[blockClass, { hover: hovering }]"
    @mouseenter="hovering = true"
    @mouseleave="hovering = false"
  >
    <div class="source">
      <slot name="source" />
    </div>
    <div ref="meta" class="meta">
      <div v-if="$slots.default" class="description">
        <slot />
      </div>
      <div class="highlight">
        <slot name="highlight" />
      </div>
    </div>
    <div
      ref="control"
      class="demo-block-control"
      :class="{ 'is-fixed': fixedControl }"
      @click="isExpanded = !isExpanded"
    >
      <transition name="arrow-slide">
        <i :class="[iconClass, { hovering: hovering }]" />
      </transition>
      <transition name="text-slide">
        <span v-show="hovering">{{ controlText }}</span>
      </transition>
      <!-- <el-tooltip effect="dark" content="前往 codepen.io 运行此示例" placement="right">
        <transition name="text-slide">
          <el-button
            v-show="hovering || isExpanded"
            size="small"
            type="text"
            class="control-button"
            @click.stop="goCodepen">
             在线运行
          </el-button>
        </transition>
      </el-tooltip> -->
    </div>
  </div>
</template>

<script>
import { stripScript, stripStyle, stripTemplate } from '@/util'
export default {
  data() {
    return {
      codepen: {
        script: '',
        html: '',
        style: ''
      },
      hovering: false,
      fixedControl: false,
      isExpanded: false,
      scrollParent: null
    }
  },
  computed: {
    blockClass() {
      return `demo-zh-CN demo-${this.$router.currentRoute.path
        .split('/')
        .pop()}`
    },
    iconClass() {
      return this.isExpanded ? 'el-icon-caret-top' : 'el-icon-caret-bottom'
    },
    controlText() {
      return this.isExpanded ? '隐藏代码' : '显示代码'
    },
    codeArea() {
      return this.$el.getElementsByClassName('meta')[0]
    },
    codeAreaHeight() {
      if (this.$el.getElementsByClassName('description').length > 0) {
        return (
          this.$el.getElementsByClassName('description')[0].clientHeight +
          this.$el.getElementsByClassName('highlight')[0].clientHeight +
          20
        )
      }
      return this.$el.getElementsByClassName('highlight')[0].clientHeight
    }
  },
  watch: {
    isExpanded(val) {
      this.codeArea.style.height = val ? `${this.codeAreaHeight + 1}px` : '0'
      if (!val) {
        this.fixedControl = false
        this.$refs.control.style.left = '0'
        this.removeScrollHandler()
        return
      }
      setTimeout(() => {
        this.scrollParent = document.querySelector(
          '.page-component__scroll > .el-scrollbar__wrap'
        )
        this.scrollParent &&
          this.scrollParent.addEventListener('scroll', this.scrollHandler)
        this.scrollHandler()
      }, 200)
    }
  },
  created() {
    const highlight = this.$slots.highlight
    if (highlight && highlight[0]) {
      let code = ''
      let cur = highlight[0]
      if (cur.tag === 'pre' && (cur.children && cur.children[0])) {
        cur = cur.children[0]
        if (cur.tag === 'code') {
          code = cur.children[0].text
        }
      }
      if (code) {
        this.codepen.html = stripTemplate(code)
        this.codepen.script = stripScript(code)
        this.codepen.style = stripStyle(code)
      }
    }
  },
  mounted() {
    this.$nextTick(() => {
      let highlight = this.$el.getElementsByClassName('highlight')[0]
      if (this.$el.getElementsByClassName('description').length === 0) {
        highlight.style.width = '100%'
        highlight.borderRight = 'none'
      }
    })
  },
  methods: {
    goCodepen() {
      const { script, html, style } = this.codepen
      console.log('script', script, html, style)
    },
    removeScrollHandler() {
      this.scrollParent &&
        this.scrollParent.removeEventListener('scroll', this.scrollHandler)
    },
    scrollHandler() {
      // const { top, bottom, left } = this.$refs.meta.getBoundingClientRect()
      // this.fixedControl =
      //   bottom > document.documentElement.clientHeight &&
      //   top + 44 <= document.documentElement.clientHeight
      // this.$refs.control.style.left = this.fixedControl ? `${left}px` : '0'
    }
  }
}
</script>

<style lang="scss">
.demo-block {
  border: solid 1px #ebebeb;
  border-radius: 3px;
  transition: 0.2s;

  &.hover {
    box-shadow: 0 0 8px 0 rgba(232, 237, 250, 0.6),
      0 2px 4px 0 rgba(232, 237, 250, 0.5);
  }

  code {
    font-family: Menlo, Monaco, Consolas, Courier, monospace;
  }

  .demo-button {
    float: right;
  }

  .source {
    padding: 24px;
  }

  .meta {
    background-color: #fafafa;
    border-top: solid 1px #eaeefb;
    overflow: hidden;
    height: 0;
    transition: height 0.2s;
  }

  .description {
    padding: 20px;
    box-sizing: border-box;
    border: solid 1px #ebebeb;
    border-radius: 3px;
    font-size: 14px;
    line-height: 22px;
    color: #666;
    word-break: break-word;
    margin: 10px;
    background-color: #fff;

    p {
      margin: 0;
      line-height: 26px;
    }

    code {
      color: #5e6d82;
      background-color: #e6effb;
      margin: 0 4px;
      display: inline-block;
      padding: 1px 5px;
      font-size: 12px;
      border-radius: 3px;
      height: 18px;
      line-height: 18px;
    }
  }

  .highlight {
    pre {
      margin: 0;
    }

    code.hljs {
      margin: 0;
      border: none;
      max-height: none;
      border-radius: 0;

      &::before {
        content: none;
      }
    }
  }

  .demo-block-control {
    border-top: solid 1px #eaeefb;
    height: 44px;
    box-sizing: border-box;
    background-color: #fff;
    border-bottom-left-radius: 4px;
    border-bottom-right-radius: 4px;
    text-align: center;
    margin-top: -1px;
    color: #d3dce6;
    cursor: pointer;
    position: relative;

    &.is-fixed {
      position: fixed;
      bottom: 0;
      width: 868px;
    }

    i {
      font-size: 16px;
      line-height: 44px;
      transition: 0.3s;
      &.hovering {
        transform: translateX(-40px);
      }
    }

    > span {
      position: absolute;
      transform: translateX(-30px);
      font-size: 14px;
      line-height: 44px;
      transition: 0.3s;
      display: inline-block;
    }

    &:hover {
      color: #409eff;
      background-color: #f9fafc;
    }

    & .text-slide-enter,
    & .text-slide-leave-active {
      opacity: 0;
      transform: translateX(10px);
    }

    .control-button {
      line-height: 26px;
      position: absolute;
      top: 0;
      right: 0;
      font-size: 14px;
      padding-left: 5px;
      padding-right: 25px;
    }
  }
}
</style>
